Drinking Water Supply inDisaster Areas

Presented by:A. Rassam, N. Mabho & K. Mafanya

Outline

Introduction

Natural disastersthe Asian Tsunami (December 26, 2004)

hurricane Katrina (August 29, 2005),

Impact on water sources Intervensions: Water supply & treatmentThreats: Waterborne diseasesConclusion

Introduction

Natural disasters such as earthquakes, hurricanes, landslides, droughts, volcanic eruptions, tornadoes and floods.

Water supply, drainage and sewerage systems severely affected.

Provision of water in emergencies more focused on ensuring adequate supply, rather than on design.

Supply of clean water is of highest priority.

Overcrowding and unhygienic practices lead to waterborne diseases.

The Asian Tsunami

Water sources: how they were affected by the disaster

The sandy coastal aquifers: The water supply in the coastal areas is heavily dependent on freshwater from these.

Aquifers stretch from 2-8 km inland.

The majority of the flooded areas were underlain by these aquifers.

Are more prevalent on the east coast where the tsunami had a major impact.

Influence of the tsunami on the coastal lagoons and associated

groundwater

Drinking Water Contaminants After Tsunami

Drinking water sources submerged with flood water and raptured piped systems containing fecal materials:

High salinity due to sea water and eroded soils.

Microorganisms: bacteria, viruses, parasites.

Taste threshold for individual ions in drinking water contributing chiefly to salinity (From WHO, 2004)

Taste threshold, mg/l

Sodium (Na) 200

Chloride (Cl) 200-300

Calcium (Ca) 100-300

Magnesium (Mg) <100

Drinking Water Contaminants After Tsunami II

Water Sources

Urban Areas: piped water systems. Eg. Jarkata 43%Rural Areas: Rivers, wells, boreholes, lakes, streams, rainwater, river

water, lake water resevoirs, tanks.

Unhygienic Practices

Informal Settlements in tents, mosques,churches, schools

Hurricane Katrina: Location

Water Contaminants in New Orleans

Enviromental Protection Agency (EPA) and Louisiana Department of Environmental Quality (LDEQ) conducted tests for biological and chemical contaminants:

High levels Eschericha Coli in sludge.

Excess levels of lead and arsenic.

Oil spills (total petroleum hydrocarbons) promoted good habitant for bacterial growth.

Contaminated Water in New Orleans

Emergency Response

Demand assessment

Water treatmentStrainingAerationStorage & SettlementFiltrationDisinfection

Collection & Storage

Demand Assessment in DisastersIndividuals Minimum for survival

Desirable emergencysupply

3-5 l/p/d15-20 l/p/d

Health centers Out-patients onlyIn-patients (excluding Cholera hospitals)

5 l/patient/d

40-60 l/patient/d

Feeding centers20-30 l/p/d

Toilet flushing water pour flush latrines 2-8 l/p/d

Cistern flush 40-50 l/p/d

Animals (approx.) Cattle Horses, mules, donkeys Sheep, goats Camels

15-25 l/h/d20-30 l/h/d

10-20 l/h/d2 l/h/d

variableIrrigation 3-6 l/m2 /d

InterventionsWater supplied to communities: WHO, UNICEF, Red-Cross, US

military, Local military & NGOs.

Water delivered in plastic bottles from Jarkata to Aceh.

Water provision for survivours livingin shacks after the Tsunami

Steel tanks of 250L/500L

Minimum supply 7L per person day.

Maximum supply 15L per person day.

Household Water treatment

Straining by cloth removal of silt and solids that contain copeheards that host guinea wormsAeration- to remove volatile substances that cause bad odour and taste e.g hydrogen sulphite and methane.CO2 also reducedStorage & settlement-in 3 safe containers system with lids for 48 hours prevents cercariae that promote Bilharzia. 50% bacteria die in such conditions

Advance Treatment of Polluted Water

Clarification:sedimentation Addition of a flocculant, eg:aluminium sulphate,allow water to settle.(pH 7.0 - 7.5 with bicarbonate, baking soda, lime)Filtration through sandRemoval approx. 1-2 log bacteria, viruses and protozoa.Set-up renewable after 1month.

Clarification

Applicable after sandfiltration.Charcoal removes colour, taste, odour.

Disinfection

Continuous Boiling for 20 min to kill viruses,cysts,worm eggs.

Chlorination: Chlorine approx. 1% in household bleach: 2.5 mg/L

0.5 mg/L free chlorine residual remaining for future contamination.

Removal of Entamoeba histolytica, a protozoan parasite .

Disinfection by Uv-radiation

Radiation and thermal treatment

5 hrs exposure todestroy and inactivate pathogens.

50°C can kill bacteria

Waterborne DiseasesRelatively high amounts of biodegradable organic carbon, warm temperatures and low residual concentrations of chlorine (< 0.2 mg/l), can permit growth of :

Legionella, causes Legionellosis through ingestion andaspiration

V. cholerae, Cholera by ingestion and skin contactAcanthamoeba,for maturity of Legionella cells

Microorganisms like E. coli and Campylobacter can accumulate in sediments and are mobilized when water flow increases. Nuisance organisms in some surface waters and during water distribution.Wounds, respiratory infections and conjuctivitis can also result.

Collection & Storage

Storage vessels for treated water should:be clean;have coversbe above ground levelbe in a cool positionbe cleaned periodicallybe mosquito proof, andbe unlikely to taint the water.

SummaryDrinking water supply in disaster areas is a challenge beacausematerials used are susceptible to fouling which can promote bacterial growth e.g hose pipes, containers, plastic tanks, valves from taps.Unhygienic and Overcrowded residence areas promote opportunistic diseases.The preparedness of the country for disasters plays a crucial role indealing with disasters.EPA & DHHS had a plan on how to tackle disaster cases.Education and training has to be offered to developing countries toimprove their water systems.Situations can be improved only if water treatment and management is taken as part of the culture.Availability of resources and knowledge on water issues can improve the countries standards on water management for a long time .

One can never be prepared enough for adisaster because it comes as a suprise!

Thank you for listening!!